Automobiles and other vehicles are often equipped with electronic cigarette lighters mounted in the dashboard. The cigarette lighter includes a socket and a removable lighter cap. The socket includes a cathode and anode, and the lighter cap includes corresponding electrical contacts for coupling with the cathode and anode. The lighter cap also includes a high-resistance element positioned in the electrical path between the contacts of the lighter cap.
When the lighter cap is activated in the socket, electrical current flows through the high-resistance element in the lighter cap, causing the high-resistance element to become glowing hot. When the lighter cap is removed from the socket and a flammable material (e.g., the tip of a cigarette) is placed in contact with the still-glowing high-resistance element, the flammable material starts to burn. Accordingly, a driver or passenger in an auto can readily use the cigarette lighter to light a cigarette.
With the rapid spread of portable electronics (e.g., portable music players, communication devices, mobile computers, etc.) in recent years, however, the cigarette-lighter socket is now widely used as a power supply. Adapters/connectors are manufactured with terminals for contacting the cathode and anode in the socket. Those terminals are coupled with wires that lead to a power connector that can be inserted into the power-input socket of a portable electronic device.
When the user inserts the adapter/connector into the socket, a spring-loaded plunger in the connector is pressed against the cathode of the socket, while spring-loaded side terminals on the connector are pressed against the anode of the socket to create a circuit from the vehicle's battery, through the socket and connector, and ultimately to the portable electronic device. Thus powered, the electronic device can be operated as intended inside the vehicle.